The measurement of various biological parameters by gas chromatography-mass spectrometry will include measurement of HVA, 5-HIAA, and MHPG in the CSF. We will also measure secondary amines and primary amines from imipramine and amitriptyline. The implementation of the clinical study of depressed patients and of comparison patients with regard to their therapeutic response to tricyclic medication given blindly will be continued. The final methods for assaying and assessing stability of the tricyclics and biogenic amines will be completed. Beginning in about a month the attempt to admit 16 new patients annually to the study and the measurements of tricyclic levels and biogenic amines of samples obtained some months ago will be done.